Improvement in thermometers



G. B. WIGGIN.

THERMOMETERS.

Pa-temen on. 2 4, 1876i.-

j (fz/y N: PErERs, PHOTO HOGRAPHER ilk 1 UNITEDiST-ATES GEORGE B. WIGGIN, OE SOUTH NEWMAEKET, ivEwHAMPsHr-'EE.4

PATENT if IMPROVEMENT IN THERMOMETERS.

. Specification formingpart of Letters Patent N o. 183,523, dated October 24, 1.8.76; application `tiled April 12,1876. Y

To all whom t may concern Be it `known that I, GEORGE B. WIGGIN, of

4 South Neu'r Market, inthe county of Rockingham and State ot'. New Hampshire, have invented anew and useful Improvement in Thermo-Motors and Thermometers, and which is set forth in the following specification, reference being had ytoY the accompanyingdrawings. The object of my invention is to provide a combination and arrangement of materials, one highly sensitive to expansion by heat, and the other very little so, the combination, as hereinafter described, being applicable and available in many branches ofthe arts and sciences where the principle of expansion or ot" differential expansion may be used to impart motion to bodies, or to indicate varying conditions due to-heat, and also applicable to actuate mechanism of such'character that the apparatus shall serve as a thermometer, dispensing with mercury or other liquid in its construction.

l In the drawings, I have illustrated my in- -vention in Figures 1 and 2 as'applied to mechanism, whereby it operates devices to indicate the thermal condition or character of the atmosphere.- Figs. 3 and 4 are plan and edge views of the thermo-motor made at instead of tubular. Fig. l is a front view of such a thermometer, and Fig. 2 a similar View with the tube in section, and the casing and dial removed to show the manner of operating mechanism through the instrumentality of an expanding body or medium acting as a thermo-motor.

A isa tube or piece ot' hard rubber, which is peculiarly sensitive to heat, readily responding even to the warmth ofthe hand when grasping it. This expansion, or its correspondent contraction, however, would be imperceptible to the touch or vision in a short tube, and therefore to Vbringit palpably to the senses I make use of suitable mechanical appliances whereby the slight increase or decrease in the length of the tube shall be represented to a multiplied extent, and lto any degree desired. B isa wooden strip or rod, Wood being selected because of its very slight capacity for longitudinal expansion or contraction. This rod extends through said tube at its open end, c, as shown, and yati-its other end it is secured by a pin, d, or otherwise, in av socket,`e, of acap,-F, which is screwed or removably attached to the outer end of the hardrubber tube. The wooden piece should be of lesser size and diameter than the bore of the hard-rubber tube, sothat it shall' preferablyvbe out of contact with such tube, and offer no obstruction to its free longitudinal expansion.: The tube A is screwed or rigidly secured in-,

to the dial frame or box, as shown at gfand the end h of the rod hasa terminal tip or pin, t', which may be lof metal Orother substance, entering acavity in the 4shortarm j of I lever K, the long arm of which connects with, a link, L. The other end of this link L islpiv to keep the lever K in contact with pin t' of the rod B, especially during the contraction of the tube A. The scale on the dial, when used for a thermometer, is, of course, graduated to correspond with that of a Fahrenheit, centigrade, or other known scale, but arranged in a circular form The operation will now be apparent. As the heat expands the tube, its length relatively to the rod is increased, but as the tube and rod are connected at one end this difference becomes available and operative at the other end, the spring turning thepinion-shaft and pointer just to an extent proportionate to the expansion. Upon a reduction ot' temperature the wooden rod pushes the lever K, actuates the pointer in the reverse direction, and rewinds the spring to the extent proportionate to the reduction of temperature.

In my motor I purposely avoid the use of two different metals for expansion purposes, as they are not reliable or accurate; nor will metal of any kind, not even steel, answer well with the rubber, because all metal will contract and expand long after the rubber, because less sensitive, and slower to respond to the action of heat and cold, and therefore the Errea;

instrument `would 4not indicate correctly, `and Wouldkeepthelgage wrong; rbut with the `Wood or glass, metal may be used.

Itwill be evident that the rod may be connected with other devices than an index or pointer, and may serve to actuate mechanism as wellas to give the measure of heataal a deep-sea thermometer, the metallic parts of the mechanism being gold-coated or otherwise, to prevent corrosion, and a stop-,hand being provided on the dial.y

My inventionis also applicable for opening and closinghotair registers for operating the valves in steam or hot-water radiators, for anycut-oi' or graduatingpurpose in buildings, cars,or `rooms heated by steam for graduating the air-slide in coal or wood stoves, and in general, wherever prompt positive `action is demanded at any predetermined `degree of temperature lessfthan thatwhich would damage the hard rubber or impair its efiiciency.

The rodrB may be madeof glass insteadof wood, and `produce equally good results Vin conjunction with the hard-rubber tube; but I prefer Wood, as'glass is liable :to get broken in The rubber and wooden rod ma;r also be employed asi transportation. The hard rubber, Ihowever, `I use in either case,;not only'because of `its extreme sensitiveness, but also because of its peculiar uniformity of action under heat and cold.

'Ihe hard rubber, as above intimated, need not necesssarily be tubular, as practically the t same resultsare attainableby Euniltingjat one end flat pieces of such rubber and Wood, of which an illustrationis given in Figs. 3 and4.

I am aware that in thermostats bars of rubber have been used, and that rubber has been used with metal, and that strips of metal have been riveted or `fastened together at both i lends or throughout their lengths.

These, therefore, I do not claim; but

I claim- 1. The described combination, Witha hardrubber strip .o r tube, yof- 'Wooden lrod, the .two

being `firmly ,connected t one Lendonly,audi

the rodrbeing elsewher free `of the rubber, and serving to `c zommunicate motion, ,derived from theexpansion or contraction of the rub,- ber, .directly tothe mechanism to be operated. `2. In `combination with `thehardrubber and the wooden rod, the ,described `system of levers, the rack, pinion-shaft, and ;pinion,1spring indicatinglhand orpointer, anddial, substan-` tiallyas and for Vthepurpose set forth.

t l,GEORGE B. `WIGrGrINl Witnesses:

H. F. DnssLAM, ALi'fmiRrr` FIELD. 

